The objective of the programme is to assess the potential of geothermal resources in the country and to harness these resources for power generation and for direct heat applications for space heating, greenhouse cultivation, cooking, etc.

Projects undertaken by the Ministry in the past have� demonstrated the applications of geothermal fluids for small-scale power generation and in poultry farming and greenhouse cultivation.

Magnetotelluric (MT) investigations to delineate sub-surface, geo-electric structures and evaluate their geothermal significance have been carried out by the National Geophysical Research Institute (NGRI), Hyderabad in Tatapani geothermal area in Chhattisgarh� and for Puga geothermal area in Ladakh Region, Jammu and Kashmir.

Similar studies are in progress for geothermal fields in the States of Surajkund in Jharkhand, Badrinath-Tapovan in Uttaranchal and Satluj-Beas and Parvati Valleys in Himachal Pradesh.

National Hydroelectric Power Corporation (NHPC), with the support from Ministry, prepared feasibility report for� development of geothermal fields in Puga, Ladakh region of Jammu & Kashmir and Tatapani geothermal field in the Surguja district of Chhattisgarh.

First, it's clean. Energy can be extracted without burning a fossil fuel such as coal, gas, or oil. Geothermal fields produce only about one-sixth of the carbon dioxide that a relatively clean natural-gas-fueled power plant produces, and very little if any, of the nitrous oxide or sulfur-bearing gases. Binary plants, which are closed cycle operations, release essentially no emissions.

Geothermal energy is available 24 hours a day, 365 days a year. Geothermal power plants have average availabilities of 90% or higher, compared to about 75% for coal plants.

Geothermal power is homegrown, reducing our dependence on foreign oil.

Being available 24 hours makes geothermal a great new renewable source of energy. Not solar not wind are available 24 hours.

2. Why is geothermal energy a renewable resource?

Answer: Because its source is the almost unlimited amount of heat generated by the Earth's core. Even in geothermal areas dependent on a reservoir of hot water, the volume taken out can be reinjected, making it a sustainable energy source.

Yes it is sustainable.

3. Where is geothermal energy available?

Answer: Hydrothermal resources - reservoirs of steam or hot water - are available primarily in the western states, Alaska, and Hawaii. However, Earth energy can be tapped almost anywhere with geothermal heat pumps and direct-use applications. Other enormous and world-wide geothermal resources - hot dry rock and magma, for example - are awaiting further technology development.

Further research can throw light on geothermal energy availability in India.

Emissions are low. Only excess steam is emitted by geothermal flash plants. No air emissions or liquids are discharged by binary geothermal plants, which are projected to become the dominant technology in the near future.

Salts and dissolved minerals contained in geothermal fluids are usually reinjected with excess water back into the reservoir at a depth well below groundwater aquifers. This recycles the geothermal water and replenishes the reservoir. The City of Santa Rosa, California, pipes the city's treated wastewater up to The Geysers power plants to be used for reinjection fluid. This system will prolong the life of the reservoir as it recycles the treated wastewater.

Some geothermal plants do produce some solid materials, or sludges, that require disposal in approved sites. Some of these solids are now being extracted for sale (zinc, silica, and sulfur, for example), making the resource even more valuable and environmentally friendly.

5. What is the visual impact of geothermal technologies?

Answer: District heating systems and geothermal heat pumps are easily integrated into communities with almost no visual impact. Geothermal power plants use relatively small acreages, and don't require storage, transportation, or combustion of fuels. Either no emissions or just steam are visible. These qualities reduce the overall visual impact of power plants in scenic regions.

6. Is it possible to deplete geothermal reservoirs?

Answer: The long-term sustainability of geothermal energy production has been demonstrated at the Lardarello field in Italy since 1913, at the Wairakei field in New Zealand since 1958, and at The Geysers field in California since 1960. Pressure and production declines have been experienced at some plants, and operators have begun reinjecting water to maintain reservoir pressure. The City of Santa Rosa, California, pipes its treated wastewater up to The Geysers to be used as reinjection fluid, thereby prolonging the life of the reservoir while recycling the treated wastewater.

7. How much does geothermal energy cost per kilowatt-hour (kWh)?

Answer: At The Geysers, power is sold at $0.03 to $0.035 per kWh. A power plant built today would probably require about $0.05 per kWh. Some plants can charge more during peak demand periods.

Isnt that awesome !?

8. What does it cost to develop a geothermal power plant?

Answer: Costs of a geothermal plant are heavily weighted toward early expenses, rather than fuel to keep them running. Well drilling and pipeline construction occur first, followed by resource analysis of the drilling information. Next is design of the actual plant. Power plant construction is usually completed concurrent with final field development. The initial cost for the field and power plant is around $2500 per installed kW in the U.S., probably $3000 to $5000/kWe for a small (<1Mwe) power plant. Operating and maintenance costs range from $0.01 to $0.03 per kWh. Most geothermal power plants can run at greater than 90% availability (i.e., producing more than 90% of the time), but running at 97% or 98% can increase maintenance costs. Higher-priced electricity justifies running the plant 98% of the time because the resulting higher maintenance costs are recovered.

9. What makes a site good for geothermal electric development?

Answer: Hot geothermal fluid with low mineral and gas content, shallow aquifers for producing and reinjecting the fluid, location on private land to simplify permitting, proximity to existing transmission lines or load, and availability of make-up water for evaporative cooling. Geothermal fluid temperature should be at least 300º F, although plants are operating on fluid temperatures as low as 210º F.

10. How much water does a plant require?

Answer: The flow required depends on the temperature of the fluid, the ambient (sink) characteristics, and the pumping power required to supply and dispose of the fluid. Excluding fluid pumping, a closed-loop binary-cycle geothermal power plant would need 450 to 600 gallons per minute (gpm) to generate 1 MW from a 300° F fluid with an air temperature of 60° F. If the fluid temperature were only 210° F, one would need 1,300 to 1,500 gpm to generate the same amount of power. If an evaporative cooling system were used, 45 to 75 gpm of make-up (clean) cooling water would also be required to generate 1 MW.

Doesnt it appear good for India. Unfortunately we are yet to locate some big finds of geothermal sites in india.

Geothermal energy is energy extracted from heat stored in
the earth. This energy originates from the original formation of the planet,
from radioactive decay of minerals, and from solar energy absorbed at the
surface. It has been used for space heating and bathing since ancient times,
but is now known for both heating as well as for generating electricity.

There are three main methods to
exploit geothermal sources:

Direct use of hot water from geothermal hot water reservoirs

Electricity from geothermal energy –Geothermal power plants
are generally built where geothermal reservoirs are located within a mile
or two of the surface, and use the reservoir heat for generating steam, which
runs a turbine to produce electricity.

Ground source heat pumps / geothermal heat pumps – These heat
pumps use the stable temperature under the ground, and the consequent
temperature difference between the surface and underground, to heat or
cool buildings.

The Indian government has done little so far to exploit
geothermal energy. Unlike in the sectors of wind and solar energy, few benefits
or incentives have been formulated or announced to attract investment in
geothermal energy.

Total available potential

Claimed to be 10,000 MW but
experts are confident only to the extent of 100 MW

Exploited potential

None

Projected capacity

No projections yet

Government incentives

10 year tax break, incentive
package still evolving

Investments

Companies that have started
exploring this field include LNJ Bhilwara, Tata Power (5MW plant in Gujarat),
Thermax (3MW plant in Ladakh) and Geosyndicate Power (25MW in Andhra Pradesh)[1]

The cost of geothermal energy can be extremely low depending on how you approach the use of this free renewable energy. Geothermal energy is heat contained within the earth, and there are a number of ways in which we can use this energy.

The most powerful method of harnessing the free geothermal energy is through the use of a geothermal power plant. The second method which is used on a much wider scale is through the use of underground pipes in an attempt to extract heat energy.

If you are a residential consumer, you are much more likely to take advantage of the energy contained within the first few meters of the ground you walk on, due to the cost it takes to go any deeper. If you are using geothermal for industry (such as a power station), you are more likely to make use of geothermal power contained deep within the earth, yet this method can be very pricey. more

How much does a geothermal power plant cost?

According to studies, an economically competitive geothermal power plant can cost as low as $3400 per kilowatt installed. (1) While the cost of a new geothermal power plant is higher than that of a comparable natural gas facility, in the long run the two are similar over time. This is because natural gas construction costs account for only one third of the total price of the facility, while the cost of the fuel at a natural gas facility represents two thirds of the cost. The initial construction costs of a geothermal facility, in contrast, represent two thirds or more of total costs. So although initial investment is high for geothermal, natural gas and geothermal are still economically comparable over a long term.

Figure 27: Levelized Costs of Selected Technologies

How much does power from a geothermal power plant cost?

California Energy Commission (CEC) 2007 estimates place the levelized (2) generation costs for a 50 MW geothermal binary plant at $92 per megawatt hour (3) and for a 50 MW dual flash geothermal plant at $88 per megawatt hour, which over the lifetime of the plant can be competitive with a variety of technologies, including natural gas. (4) According to the CEC report, natural gas costs $101 per megawatt hour for a 500 MW combined cycle power plant and $586 per megawatt hour for a 100 MW simple cycle plant. On average the cost for new geothermal projects ranged from 6 tp 8 cents per kilowatt hour according to a 2006 report, including the production tax credit. (5) But, it should be noted that the cost for individual geothermal projects can vary significantly based upon a series of factors discussed below, and that costs for all power projects change over time with economic conditions.

"However, it must be remembered that a major impact on geothermal power cost is the local, regional, national, and global competition for commodities such as steel, cement, and construction equipment. Geothermal power is competing against other renewable and non-renewable power development, building construction, road and infrastructure improvements, and all other projects that use the same commodities and services. Until equipment and plant inventories rise to meet the increase in demand for these commodities and services, project developers can expect the costs to rise well above the background inflation level."

Geothermal power plants are characterized by high capital investment for exploration, drilling wells, and plant installation, but low cost for operation and maintenance. In 2001, EPRIestimated that capital reimbursement and associated interest account for 65% of the total cost of geothermal power. (8) Capital costs of a combined cycle natural gas power plant, in contrast, only represents about 22% of the levelized cost of electricity produced from the plant, while the fossil fuel cost accounts for 67% . (9) However, geothermal plants have no fuel costs, and over a typical 30-year plant life the fuel costs for a natural gas or coal plant can represent twice their initial capital cost. Over the life of the plant, when you consider capital costs and total fuel costs, geothermal projects can be a sound investment.

Geothermal energy is defined as heat from the Earth. It is a clean, renewable resource that provides energy in the U.S. and around the world in a variety of applications and resources. Although areas with telltale signs like hot springs are more obvious and are often the first places geothermal resources are used, the heat of the earth is available everywhere, and we are learning to use it in a broader diversity of circumstances. It is considered a renewable resource because the heat emanating from the interior of the Earth is essentially limitless. The heat continuously flowing from the Earth’s interior, which travels primarily by conduction, is estimated to be equivalent to 42 million megawatts (MW) of power, and is expected to remain so for billions of years to come, ensuring an inexhaustible supply of energy. (1)

A geothermal system requires heat, permeability, and water. The heat from the Earth's core continuously flows outward. Sometimes the heat, as magma, reaches the surface as lava, but it usually remains below the Earth's crust, heating nearby rock and water — sometimes to levels as hot as 700°F. When water is heated by the earth’s heat, hot water or steam can be trapped in permeable and porous rocks under a layer of impermeable rock and a geothermal reservoir can form. This hot geothermal water can manifest itself on the surface as hot springs or geysers, but most of it stays deep underground, trapped in cracks and porous rock. This natural collection of hot water is called a geothermal reservoir.

Estimates of the electricity generating potential of geothermal energy vary from 35 to 2,000 GW.[2] Current worldwide installed capacity is 10,715 megawatts (MW), with the largest capacity in the United States (3,086 MW),[3]Philippines, and Indonesia.

Geothermal power is considered to be sustainable because the heat extraction is small compared with the Earth's heat content.[4] The emission intensity of existing geothermal electric plants is on average 122 kg of CO2 per megawatt-hour (MW·h) of electricity, about one-eighth of a conventional coal-fired plant.